I'm wondering if anyone else has had issues with there speedo being off. When I go past local radar my speedo says 37 and the radar shows 33, I have done this on several different radars and they all show the same margin of error.

My unscientific observations indicate a 5% to 7% off-set based on random GPS comparisons and using stationary Radar speed signs. This is typical of all bikes I've ridden and tested.

Does the owners manual state the exact percentage of speedo off-set built into the ECU?

As stated correctly, ALL manufacturers off-set speedo readings optimistically, usually between 5% up to 10%. But ODO readings will be accurate (providing tires are stock size)

So far, I've hit 130 mph indicated on my HyperStrada. So I guess about 124 mph actual? Not bad! Wind blast about ripped me off the bike. (this done prone, head down under screen) I think in calm weather could have gone a bit more. Did not note RPM.